"Oh, he is marvellous, he knows his household pests, all right, it's a wonderful book..."
-- Molly Weasley (CS3)
Gilderoy Lockhart’s Guide to Household Pests is a guide to various common magical pests.
Mrs. Weasley keeps a copy of this. It discusses gnomes (CS3) and Doxies (OP6).
Like all of Lockhart's books, the cover displays a large photograph of Gilderoy himself "winking cheekily", and has the title written in "fancy gold letters" (CS3).
Commentary
Notes
It seems ironic, given Lockhart's true nature, that this book is so useful. All of his other works that we know about are written in a memoir style (easy to fake by just writing out stories other people have told him), whereas this book actually requires knowledge and expertise in the area. Was someone else perhaps working on researching and writing a pest guide, and mysteriously forgot about it? --RP